Hey man im sorry to hear this is happening to you. For reference, I’m 6’0, and my wife is 5’1. Our height difference hasn’t made any difference in any position, we can hit all of them. Some we need pillows under her stomach or legs or butt, but we’ve been able to hit all of them. The pillows do help through, and you can angle towards the g-spot more effectively. But to the other issue, her just laying there. That’s absolutely not a height thing. She’s likely just insecure because she’s probably only ever had guys want to do things to her, not with her. There’s a lot she can do, from oral to stimulation of your erogenous zones, to riding, or even something like her bucking her hips against you to match your cadence. It amplifies everything. An arm around you, a leg to pull you deeper ect. This would best be talked about in a more serious, but safe and comforting situation down talk where you discuss you wanting to try these things with her. Discuss why it would be hot for you, how attractive she is and would be doing these things and how it would help you feel wanted sexually too. Communication is the foundation for any relationship